scholarly journals Mode of formation of cholesta-5,7-dien-3β-ol from cholest-5-en-3β-ol by larvae of Calliphora erythrocephala

1975 ◽  
Vol 152 (2) ◽  
pp. 303-311 ◽  
Author(s):  
Paul Johnson ◽  
Ian F. Cook ◽  
Huw H. Rees ◽  
Trevor W. Goodwin
Keyword(s):  
Hydrogen Atom ◽  
Bond Formation ◽  
Calliphora Erythrocephala ◽  
Probable Role ◽  
Esterified Sterols

1. The conversion of cholest-5-en-3β-ol (cholesterol) into cholesta-5,7-dien-3β-ol by axenic Calliphora erythrocephala larvae was demonstrated. 2. The transformation is probably direct (Δ5→Δ5,7) and does not involve a Δ0 intermediate (Δ5→Δ0→Δ7→ Δ5,7). 3. Δ7-bond formation involves the stereospecific elimination of the 7β hydrogen atom. 4. The relative amounts of free and esterified sterols were determined in larvae grown on cholesterol as sole sterol source and on 5α-cholestan-3β-ol supplemented with minimal amounts of cholesterol. 5. The significance of the results is assessed in relation to the probable role of cholesta-5,7-dien-3β-ol as an intermediate in the biosynthesis of ecdysones.

A Probable Role of Eosinophilia, IgE and Complement in Bullous Pemphigoid Patients

1975 ◽  
Vol 37 (4) ◽  
pp. 532-540 ◽  
Author(s):  
Zenro IKEZAWA ◽  
Yo KAMEDA ◽  
Mitsuaki UCHIYAMA ◽  
Hiroshi NAKAJIMA ◽  
Toru BABA
Keyword(s):  
Bullous Pemphigoid ◽  
Probable Role

Beyond peptide bond formation: the versatile role of condensation domains in natural product biosynthesis

2021 ◽  
Author(s):  
Sofie Dekimpe ◽  
Joleen Masschelein
Keyword(s):  
Natural Product ◽  
Bond Formation ◽  
Peptide Bond ◽  
Chemical Diversity ◽  
Peptide Bond Formation ◽  
Natural Product Biosynthesis

Condensation domains perform highly diverse functions during natural product biosynthesis and are capable of generating remarkable chemical diversity.

Topography of the Free Energy Landscape on the Claisen-Schmidt Condensation: Solvent and Temperature Effect in the Rate-Controlling Step

2021 ◽  
Author(s):  
Nayara Dantas Coutinho ◽  
Hugo Gontijo Machado ◽  
Valter Henrique Carvalho-Silva ◽  
Wender A. Silva
Keyword(s):  
Free Energy ◽  
Temperature Effect ◽  
Strong Influence ◽  
Aldol Condensation ◽  
Energy Landscape ◽  
Bond Formation ◽  
Free Energy Landscape ◽  
Rate Controlling Step ◽  
Formation Step

Recent studies have assigned hydroxide elimination and C=C bond formation step in base-promoted aldol condensation the role of having a strong influence in the overall rate reaction, in contrast to...

scholarly journals Probable role of Brain Natriuretic Peptide (BNP) in lung hypertension secondary to scleroderma

2013 ◽  
pp. 23-25
Author(s):  
P. Faggioli ◽  
S. Finazzi ◽  
E. Vicenzi ◽  
L. Giani ◽  
M. Rondena ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Progressive Systemic Sclerosis ◽  
New Drugs ◽  
Positivity Ratio ◽  
Probable Role ◽  
Biochemical Observation ◽  
And Gender ◽  
Roche Diagnostics ◽  
Worse Prognosis

BACKGROUND Scleroderma, when complicated with pulmonary hypertension (PHT), presents a worse prognosis; recently treatment with new drugs seems to offer good perspectives, especially in early diagnosis and treatment. The standard approach for diagnosing PHT consists in measurement of the pulmonary artery pressure (PAP) by means of echodoppler. AIM OF INVESTIGATION Aim of this work is evaluating the significance of the NT-proBNP parameter, matched to echodoppler, in diagnosing scleroderma PHT. MATERIALS AND METHODS Sixty (60) patients, who came to observation for progressive systemic sclerosis underwent echodoppler in order to measure the PAP (normal values up to 30 mmHg). NT-proBNP was determined on serum sample using ECLIA method by Modular E170 (Roche Diagnostics); manufacturer reference values for age and gender were used. Forty-three (43) patients underwent a further NT-proBNP sampling 5 days later in order to assess parameter stability. RESULTS PHT and non- PHT patients showed statistically different (p < 0,001) medians (126 vs 69 pg/ml). No pathologic values of NT-proBNP were measured in the group with PAP < 30 mmHg, while 27% of cases who had PAP between 30 and 40 showed pathologic concentrations. The positivity ratio increases to 57% in patients showing PAP > 40 mmHg. No relevant correlation (r = 0,2) was found between PAP and NT-proBNP. Mean average between the two sampling groups was 31%. CONCLUSIONS In scleroderma patients, combination of NT-proBNP and PAP seems to improve the diagnosis of pulmonary hypertension, especially in presence of borderline pulmonary pressure values. We therefore propose the biochemical observation of NT-proBNP when PAP is > 30 mmHg and in monitoring the evolution of the pathology.

Folding of peptides and proteins: role of disulfide bonds, recent developments

2013 ◽  
Vol 4 (6) ◽  
pp. 597-604 ◽  
Author(s):  
Yuji Hidaka ◽  
Shigeru Shimamoto
Keyword(s):  
Protein Folding ◽  
Disulfide Bonds ◽  
Bond Formation ◽  
Difficult Problem ◽  
Chemical Methods ◽  
Mutant Proteins ◽  
Folding Intermediates ◽  
Peptide Chemistry ◽  
Recent Developments

AbstractDisulfide-containing proteins are ideal models for studies of protein folding as the folding intermediates can be observed, trapped, and separated by HPLC during the folding reaction. However, regulating or analyzing the structures of folding intermediates of peptides and proteins continues to be a difficult problem. Recently, the development of several techniques in peptide chemistry and biotechnology has resulted in the availability of some powerful tools for studying protein folding in the context of the structural analysis of native, mutant proteins, and folding intermediates. In this review, recent developments in the field of disulfide-coupled peptide and protein folding are discussed, from the viewpoint of chemical and biotechnological methods, such as analytical methods for the detection of disulfide pairings, chemical methods for disulfide bond formation between the defined Cys residues, and applications of diselenide bonds for the regulation of disulfide-coupled peptide and protein folding.

First-principles insights into role of hydrogen atom in black titania

2017 ◽  
Vol 139 ◽  
pp. 84-88 ◽  
Author(s):  
S. Samaneh Ataei ◽  
S. Javad Hashemifar ◽  
Mohammad Reza Mohammadizadeh
Keyword(s):  
Hydrogen Atom ◽  
First Principles

ChemInform Abstract: C-C Bond Formation via C-H Bond Activation under Protic Conditions: The Role of Phosphane Ligand and Cosolvent.

ChemInform ◽  
2010 ◽  
Vol 41 (18) ◽  
Author(s):  
Marc-Olivier Simon ◽  
Remi Martinez ◽  
Jean-Pierre Genet ◽  
Sylvain Darses
Keyword(s):  
Bond Activation ◽  
Bond Formation

scholarly journals Role of disulfide bond formation in the folding and assembly of the envelope glycoproteins of a pestivirus

2002 ◽  
Vol 296 (2) ◽  
pp. 470-476 ◽  
Author(s):  
Norica Branza-Nichita ◽  
Catalin Lazar ◽  
David Durantel ◽  
Raymond A Dwek ◽  
Nicole Zitzmann
Keyword(s):  
Disulfide Bond ◽  
Bond Formation ◽  
Envelope Glycoproteins ◽  
Disulfide Bond Formation

scholarly journals Spinal Tolerance and Dependence: Some Observations on the Role of SpinalN-Methyl-D-Aspartate Receptors and Phosphorylation in the Loss of Opioid Analgesic Responses

2000 ◽  
Vol 5 (1) ◽  
pp. 33-39
Author(s):  
Tony L Yaksh ◽  
Xiao-Ying Hua
Keyword(s):  
Nmda Receptor ◽  
Opioid Analgesic ◽  
Dose Effect ◽  
Concurrent Treatment ◽  
Analgesic Effects ◽  
Delta Opioids ◽  
Probable Role ◽  
Pkc Isozymes ◽  
The Right

The continuous delivery of opiates can lead to a reduction in analgesic effects. In humans, as in other animals, some component of this change in sensitivity seems likely to have a strong pharmacodynamic component. Such loss of effect, deemed to be tolerance in the present article, can be readily demonstrated in animals with repeated bolus and continuous intrathecal infusion of mu and delta opioids and alpha-2 adrenergic agonists. Research has shown that this loss of effect can be diminished by concurrent treatment withN-methyl-D-aspartate (NMDA) receptor antagonists and by the suppression of the activity of spinal protein kinase C (PKC). This suggests in part the probable role of PKC-mediated phosphorylation in the right shift in the dose-effect curves observed with continuous opiate or adrenergic exposure. Importantly, this right shift is seen to occur in parallel with an increase in the phosphorylating activity in the dorsal horn and in the expression of several PKC isozymes. The target of this phosphorylation is not certain. Phosphorylation of the NMDA receptor enhances its functionality, while phosphorylation of the opioid receptor or associated channels seems to diminish their activity or to enhance internalization. While the focus is on several specific components, the accumulating data emphasize the biological complexity of these changes in spinal drug reactivity.

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